In a communication system such as Long Term Evolution (LTE) and LTE-Advanced (LTE-A), specified in the Third Generation Partnership Project (3GPP), a terminal apparatus (UE: User Equipment) uses a Scheduling Request (SR) or a Buffer Status Report (BSR) to request a radio resource for transmitting uplink data from a base station apparatus (eNodeB: evolved Node B). The base station apparatus gives uplink transmission permission (UL Grant) to each terminal apparatus on the basis of a SR and a BSR. Upon receiving the control information on the UL Grant from the base station apparatus, the terminal apparatus transmits the uplink data with a prescribed radio resource on the basis of the uplink transmission parameter included in the UL Grant.
In a case that the uplink data has been correctly received, the base station apparatus transmits an Acknowledgement (ACK) in the downlink to the terminal apparatus after a prescribed time from the reception of the uplink data. On the other hand, in a case where the uplink data could not be correctly received, the base station apparatus transmits a Negative Acknowledgement (NACK) to the terminal apparatus after a prescribed time from the reception of the uplink data. Upon receiving the NACK, the terminal apparatus retransmits the data related to the uplink data. In this manner, the base station apparatus controls all the uplink data transmissions (data transmission from the terminal apparatus to the base station apparatus). Orthogonal Multiple Access (OMA) is realized by the base station apparatus controlling uplink radio resources.
In the 3GPP, radio access technology for realizing Massive Machine Type Communication (mMTC) is being specified as the fifth generation mobile communication system (5G) (NPL 1). In mMTC, it is assumed that many devices such as terminal apparatuses and sensors transmit and receive small data. Grant-free Non-Orthogonal Multiple Access (NOMA) is being studied for the purpose of uplink mMTC (NPL 2). The grant-free Non-Orthogonal Multiple Access allows data transmitted from terminal apparatuses exceeding the number of receive antennas of the base station apparatus to be non-orthogonally multiplexed in space. In the grant-free Non-Orthogonal Multiple Access, the terminal apparatus transmits the uplink data to the base station apparatus without performing SR transmission, UL Grant reception, or the like. Therefore, even in a case that many devices transmit and receive small size data, grant-free Nonorthogonal Multiple Access is capable of suppressing an increase in overhead due to control information. Furthermore, in grant-free Non-Orthogonal Multiple Access, since UL Grant reception or the like is not performed, a period of time when transmission data is generated to when the data is transmitted may be shortened.